[Co(pdmma)(ampy)Cl]^(2+)体系——面式异构体的结构解析及其优势构型

Assignment and configuration preference of a fac-isomer in the [Co(pdmma)(amp)Cl]^(2+) system

合成了[Co(N-(2-吡啶基甲基)-N,N-二甲基乙二胺)(2-(氨基甲基)吡啶)Cl] [ZnCl4]体系的三个异构体,将配合物用H2ZnCl4结晶,1H NMR检测表明它们是标题体系中的异构体,并利用二维核磁共振技术与单晶X ray衍射法平行解析了——异构体的结构,确定其结构f2,结果显示结构中存在C-H…π相互作用．用量子化学从头计算方法,在赝势基组RHF／LANL2DZ的水平上对体系的十个可能的几何异构体(四个经式异构体和六个面式异构体)进行了结构优化及基态能量计算,f2’;f3;m3;m4四个异构体的基态能量比其他异构体低,其中f2’为最低．因此CH…π相互作用对含吡啶环的[CoN5 Cl]2+系配合物的异构体的选择性形成及其稳定性具有重要作用．

Three geometric isomers of a new [Co（pdmma）（amp）Cl[ZnCl4] system have been synthesised （ pdmrna = N- （2-pyridyltnethyl） N, N-dimethyl-ethylenediamine; amp= 2- （Aminomethyl） pyridine）. The tetrachloride zincate salt of these complexes have been suggested to be the isomers with C-H...πstructure in title system by using 1H NMR spectra. And one of these isomers （f2）was assigned by using 2D NMR technique and single crystal X-ray diffraction. The results show that C-H…π interaction exists in the title isomer. The computational results for the ten possible geometric isomers （four mer-isomers and six facial-isomers） in thissystems have been obtained by using an ab initio at RHF/LANL2DZ level. Although the total energies of the isomers f2, f3＇, m3, m4 are lower than other isomers in these two systems, For this system, the isomer f2 has the lowest of total energy in the four isomers. It shows that stability and isomeric preference of isomer are related to the C-H…πinteraction in the isomer.